This article provides an overview of a commercial 3D X-ray system, explaining how it acquires high-resolution images of submicron defects in large intact samples. It presents examples in which the system is used to reveal cracks in thin redistribution layers, voids in organic substrates, and variations in TSV metallization on 300-mm wafers. As the authors explain, each scan can be done in as little as a few minutes regardless of sample size, and the resulting images are clear of the beam hardening artifacts that often cause problems in failure analysis and reverse engineering.

X-ray ptychography, as recent studies show, has the potential to bridge the gap that currently exists between conventional X-ray imaging and electron microscopy. This article covers the evolution of the technology from basic 2D imaging to computed tomography to 3D ptychographic X-ray laminography (PyXL) with zoom. To demonstrate the capabilities of PyXL, a 16-nm FinFET logic IC was mechanically polished to a thickness of 20 µm and several regions were imaged at various levels of resolution.

Modified Talbot X-ray interferometry provides three contrast modes simultaneously: absorption, phase, and dark field/scattering. This article describes the powerful new imaging technique and shows how it is used to characterize various types of defects in advanced semiconductor packages.

Deprocessing of ICs is often the final step for defect validation in FA cases with limited fault-isolation information. This article presents a workflow for deprocessing ICs from the backside using automated thinning and large-area plasma FIB delayering. Advantages to this approach include a reduction in manual planarization and depackaging and a higher degree of precision and repeatability.

The complexity of sample preparation and deprocessing has risen exponentially with the emergence of 2.5-D and 3D packages. This article provides answers and insights on how to deal with the challenges of increasingly complex semiconductor packages. After identifying pressing issues and potential bottlenecks with state-of-the-art FA flows, the authors present two case studies demonstrating the capabilities of electro-optical terahertz pulse reflectometry (EOTPR), plasma FIB milling, and 3D X-ray imaging. The FA results confirm the potential of all three techniques and indicate that a fully nondestructive integration flow for 3D packages may be achievable with further development and optimization.

It seems that scaling of chip technology according to Moore’s Law will continue for digital functionalities (logic and memory); however, increasing system integration on chip and package levels, called “More than Moore,” has been observed in the past several years. This strong trend in the worldwide semiconductor industry enables more functionality, diversification, and higher value by creating smart microsystems. This article discusses the many challenges faced in FA of 3-D chips, where well-staffed and equipped FA labs are essential. Furthermore, FA is becoming an important strategic enabling factor for new products, not just another “cost factor.”

X-ray computed tomography is a noninvasive technique that can reveal the internal structure of objects in three dimensions with spatial resolution down to 50 nm. This article discusses the basic principles of this increasingly important imaging technology and presents examples of its use on various types of defects in semiconductor packages.

X-ray tomography has been rapidly gaining acceptance in the semiconductor industry since the first demonstration of its use on IC interconnect in 1999. As failure analysts are discovering, X-ray imaging is more powerful than visible light microscopy and can be used to analyze larger samples than those that fit in an electron microscope. This article provides an introduction to the physics, signal processing, and algorithms involved in X-ray imaging and tomography and the factors that affect resolution.